The horn on a commuter train emits sound with a frequency of 342.5 hz when the train is at rest. the train sounds its horn as it passes a passenger platform at a constant speed of 41 m/s. what overall change in frequency is detected by a person on the platform as the train moves from approaching to receding? remember that change of frequency means the final frequency minus the initial frequency. be sure to include the correct sign on the answer. (take the speed of sound to be 345 m/s.)

Which are examples of projectile motion? choose all that apply a. a soccer ball rolling across the ground in the northeast direction b. a car turning a corner, so it is heading south c. a javelin flying through the air d. a tennis ball lobbed over the net

Ais not a compound machine. a. bolt b. shovel c. handcart (dolly) d. see-saw (teeter totter)

Very large accelerations can injure the body, especially if they last for a considerable length of time. one model used to gauge the likelihood of injury is the severity index ( ), defined as =/ . in the expression, is the duration of the accleration, but is not equal to the acceleration. rather, is a dimensionless constant that = the number of multiples of that the acceleration is equal to.in one set of studies of rear-end collisions, a person's velocity increases by 13.7 km/h with an acceleration of 36.0 m/s2 . let the + direction point in the direction the car is traveling. what is the severity index for the collision?